JAKARTA, Indonesia --Australia, Indonesia and the United States have all welcomed the capture of senior al Qaeda operative Hambali, describing the arrest as a major breakthrough in the war on terrorism, but with a note of caution that further attacks may be imminent.

In the United States, President George W. Bush described Hambali as "one of the world's most lethal terrorists" and a key figure in al Qaeda's global operations.

Speaking to U.S. troops in San Diego he said Hambali was "a known killer" and "a close associate of September 11 mastermind Khalid Shaikh Mohammed."

Hambali, also known as Riduan Isamuddin, was arrested by Thai authorities two days ago in the central town of Ayutthaya, and was handed over to the CIA, according to U.S. officials. (Asia's most wanted man caught)

"He is no longer a problem to those of us who love freedom," Bush said.

Bush's comments were echoed by Australian Prime Minister John Minister who said Hambali was a "very big fish."

"There should be universal relief and pleasure that a man as evil as Hambali has been caught," Howard told reporters at the Pacific Islands Forum in Auckland, New Zealand.

"Psychologically, this capture will inflict a very heavy blow on the worldwide terrorist network," he said.

Intelligence experts have long suspected Hambali of being al Qaeda's point man in Southeast Asia; its mastermind and operations planner for the region; and its key link with the regional terror group Jemaah Islamiyah (JI).

Wanted in several countries across Asia, Hambali was thought to have been a key player in last year's Bali bombings which killed 202 people, including 88 Australians, as well as a spate of other attacks in the region. (Profile)

Indonesia, for its part, welcomed Hambali's capture as "an important mark in the global fight against terror."

Speaking in Jakarta, Foreign Ministry spokesman Marty Natalegawa said Indonesia was keen to quiz Hambali about plans for future attacks, but he added a note of caution saying the threat of further terrorist attacks remained high.

"Without wishing to exaggerate the extent to which the arrest of one individual could (help) in ensuring an end to acts of terror, at the same time it is far better to have individuals such as him under custody," he added.

In the Philippines, the government also sounded a note of caution, although it said the arrest had dealt the "world terrorist network" a big blow.

"We should not let our guard down," National Security Adviser Roilo Golez told Reuters. "We have to raise the alert level against repercussions or retaliatory attacks."

'Bin Laden equivalent'

Hambali has been the Eastern version of Osama bin Laden

-- Alexander Downer, Australian Foreign Minister

Australian Foreign Minister Alexander Downer also said the arrest would have a major impact on JI's fundraising capability and "substantially downgrade" its ability to wage terrorist operations.

"This is the equivalent of catching Osama bin Laden really, because Hambali has been the Eastern version of Osama bin Laden," he told Melbourne's radio 3AW.

Also in Australia, U.S. Deputy Secretary of State Richard Armitage said Hambali's capture would "shed light" on terrorist operations in the region and upset the flow of funds to terror groups.

Armitage, in Australia for talks on terrorism and regional security, said the arrest would force al Qaeda and JI to "come up with workarounds to their normal facility for passing money, and that's a good thing because it possibly could show up more readily to us."

New Zealand's foreign minister Phil Goff sounded a note of caution however warning that Hambali's arrest could be too late to stop any attacks planned to coincide with Indonesia's National Day on Sunday.

"Any action that may be planned will already be under way," Goff told Reuters in Auckland.

Australia and New Zealand have both warned their citizens of the possibility of attacks timed to coincide with the weekend celebrations.